I keep the HF float chargers on everything that is not used frequently. Have not had a prob since I started using them maybe 8-10y ago. Yeah, laugh about HF, but I have not seen any evidence that the premium chargers are better, sorry.
Harbor Freight electrical stuff is not a laughing matter to me. Those cheap chargers may or may not burn the garage down, but I sure wouldn't trust them. Also, their output can apparently vary quite a bit.
It's great that they have worked for you, but there are definitely superior maintainers out there. Ones with desulfation and carefully calculated charge curves (voltage, amps, temp). It's a bit like comparing a Yugo to a Challenger, I think.
Yes, both are cars and in theory both will get you to where you're going, but there are notable differences between them. Is a $20 (when on sale) BatteryMINDer really that much better than a $8 HF one? Absofriggin'lutely yes.
To be really nice to some of my batteries I use PulseTech maintainers that cost around ten times of a HF one. Are they worth it? With some 80 batteries to take care of, wanting them to last and perform as well as possible, I'd say yes they are. You may disagree.